This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. Heart failure with a normal ejection fraction (HFNEF, previously termed diastolic heart failure), accounts for the majoirty of heart failure cases in the population >65 years old and has been recognozed as a true geriatric syndrome. Exercise intolerance is the primary chronic symptom of HFNEF and a major determinant of these patients'severly reduced quality of life;however little is known regarding its pathophysiology and treatment. The aims of the proposed study are to conduct a randomized, controlled, single-blinded, 2x2 design trial to examine the effects of weight loss via hypocaloric diet, aerobic exercise training, combined hypocaloric diet and exercise training, and attention control in 100 patients with HFNEF and body mass index >30 in order to test the following hypotheses: 1. Both weight loss and exercise training will improve exercise intolerance and quality of life in older obese patients with HFNEF. 2. The combination of weight loss and exercise training will produce complementary effects on body and thigh muscle composition and additive improvements in exercise intolerance in HFNEF. 3. Improvements in exercise intolerance will correlate with improvments in lean body mass, reversal of adverse thigh muscle remodelling, and increased thigh muscle capillarity.